A vacuum rotary dryer generally includes a rotary drum including a jacket of a double peripheral wall structure in which hot water is flowed to heat it and a pressure reducing unit for reducing a pressure in the rotary drum and is adapted to dry a material to be treated or dried (or treated or dried material) which is received in the rotary drum while reducing a pressure in the rotary drum.
Such a vacuum rotary dryer exhibits advantages such as saving of energy required for drying of a treated material, a reduction in drying time, minimizing of a water content of a product, complete removal of an organic material and a solvent from a treated material, elimination of oxidation of a treated material and firing thereof due to oxygen in air, low-temperature drying of a treated material, and the like, because it is constructed to dry a material while reducing a pressure in the rotary drum.
Thus, such a dryer is extensively applied to manufacturing of pharmaceuticals in which it is highly required to prevent a deterioration in quality of pharmaceuticals due to oxidation and contamination thereof due to inclusion of any impurity therein or adhesion of bacteria thereto or the like.
In manufacturing of pharmaceuticals, it is required to minimize or substantially prevent contact of a product with the hands or an ambient atmosphere during a manufacturing process. Unfortunately, the conventional vacuum rotary dryer described above needs manual operation in charging of a treated material or treated solids into the rotary drum and removal of the solids dried from the rotary drum, resulting in failing to prevent contact of the solids with the hands and an ambient atmosphere.
Also, the conventional vacuum rotary dryer fails in automation of a drying step because it requires manual operation in charging of a treated material or treated solids into the rotary drum and removal of the solids dried from the rotary drum. Thus, the drying step is deterrent to automation of manufacturing facilities.
An object of the present invention is to provide a vacuum rotary dryer which is capable of permitting all steps extending from charging of solids to a rotary drum to removal of the solids therefrom to be carried out without any manual operation.